133 



the fact, that the animal he has given, is, in truth, the animal of P. 

 ancillaria, and not that of P. heterostropha, as he states ; at least, 

 of all the specimens of this omnipresent species, which I have ob- 

 served, I have never seen an animal like that of the figure ; whereas 

 it is like the few specimens of P. ancillaria, which I have met 

 with, and which is described in the ' Report on the Invertebrata of 

 Mass.,' to be lemon yellow." 



At the request of Dr. Gould, Mr. Thomas McCulloch, Jr., 

 of Halifax, Nova Scotia, read a paper "On the importance 

 of Habit, as a guide to accuracy in systematical arrange- 

 ment : illustrated in the instance of the Sylvia petechia of 

 Wilson and all subsequent writers." 



The S. petechia differs little in external development from the 

 true Sylvicola?, but, as shown by the evidence of habit, belongs to 

 the small genus Seiurus of Swainson. The characteristics of this 

 genus are chiefly indicated by habit; and these, by the bird above- 

 mentioned, are exhibited quite as forcibly as by either of its con- 

 geners. Mr. McCulloch gave in support of his opinion, a minute 

 and interesting detail of the habits of the bird, as observed by him- 

 self at various seasons, particularly at the pairing season. He 

 concluded by expressing his regret at the necessity of disturbing, 

 in any case, scientific arrangements which have long been acqui- 

 esced in, but, at the same time, his conviction that accuracy, in this 

 instance, requires the change. 



On motion of Dr. C. T. Jackson, the thanks of the Soci- 

 ety were presented to Mr. McCulloch, for his communica- 

 tion, and a copy was requested for publication in the Jour- 

 nal of the Society. 



The President, to whom had been committed a paper en- 

 titled ' : Descriptions of seven species of shells, regarded as 

 new by Dr. J. W. Mighels, of Portland," reported thereon, 

 expressing a doubt whether all the species described by Dr. 

 Mighels, would prove to be new, but recommending the 

 publication of the paper in the Journal. 



